Fluid actuated piston valve

ABSTRACT

A piston valve of the kind in which a piston is movable longitudinally of a housing having ports for fluid to be controlled by the piston between two operative positions in each of which at least some of said ports are interconnected in different pairs through passages in the piston, by actuating fluid pressure applied to the end of the piston appropriate to the movement required, the actuating fluid pressure for effecting the movement in one direction being applied from a source externally of the valve and the actuating fluid pressure for effecting movement in the other direction being derived from one of said ports when the piston has been moved in said one direction. Said one port is connected to an end portion of the housing adjacent the relevant end face of the piston through a restricted passage and a closable control orifice leads from the passage between the restriction therein and said end portion of the housing, the control orifice being openable to prevent the actuating fluid pressure from rising sufficiently to effect movement of the piston in said other direction and closable to permit the actuating fluid pressure to reach a value sufficient to effect movement of the piston in said other direction when said movement is to be effected.

United States Patent Kirk [54] FLUID ACTUATED PISTON VALVE [72]Inventor: Colin John Kirk, Whispers," 125 Dukes Ride, Crowthorne,England 7 [22] Filed: Aug. 14, 1970 [21] Appl. No.: 63,861

[30] Foreign Application Priority Data Aug. 26, 1969 Great Britain......42,403/69 [52] U.S.Cl. ..l37/l19,9l/189, 137/624.18, 137/625.61 [51]int. Cl ..FlSb 21/02 [58] Field oiSenrch ..137/87,115, 119, 625.61,624.18; 91/189 [56] References Cited UNITED STATES PATENTS 3,457,9417/1969 Cook ..417/307 X 3,565,114 2/1971 Rousseau... .....91/189X2,625,136 1/1953 Moog ..137/625.6l 2,934,765 4/1960 Carson.....137/625.61 3,055,383 9/1962 Paine .137/62561 X 3,509,899 5/1970 Hewson..137/87 OTHER PUBLICATIONS 1 June 13, 1972 Primary Examiner-M. CaryNelson Assistant Examiner-David J. Zobkiw Attomey-Mawhinney & MawhinneyABSTRACT A piston valve of the kind in which a piston is movablelongitudinally of a housing having ports for fluid to be controlled bythe piston between two operative positions in each of which at leastsome of said ports are interconnected in different pairs 1 throughpassages in the piston, by actuating fluid pressure applied to the endof the piston appropriate to the movement required, the actuating fluidpressure for effecting the movement in one direction being applied froma source externally of the valve and the actuating fluid pressure foreffecting movement in the other direction being derived from one of saidports when the piston has been moved in said one direction. Said oneport is connected to an end portion of the housing adjacent the relevantend face of the piston through a restricted passage and a closablecontrol orifice leads from the passage between the restriction thereinand said end portion of the housing, the control orifice being openableto prevent the actuating fluid pressure from rising sufiiciently toeffect movement of the piston in said other direction and closable topermit the actuating fluid pressure to .reach a value sufficient toefiect movement of the piston in said other direction when said movementis to be effected.

4 Claims, 7 Drawing Figures n1 g g PATENTEDJUN13 I972 3.669.137

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INVENTag 4 COLIN JOHN \qzvr PATENTEDJUH13 I972 3,669.13 7

sum 2 OF 3 MVENTQ Couw JOHN \KR' PATENTEDJUN 1 3 I972 sum 3 0F 3 Co muJQ FLUID ACTUATED PISTON VALVE The invention relates to a piston valveof the kind comprising a housing having a plurality of ports in itsperipheral wall between which theflow of fluid is controlled by a pistonin the housing, the piston being movable longitudinally of the hous ingbetween two operative positions, in each of which at least some of saidports are interconnected in different pairs through passages in saidpiston, by actuating fluid pressure applied to one or other end of thepiston according to the direction of movement required.

It has been proposed hitherto to apply an actuating fluid pressure toone end face of a piston of such a valve through a separate controlvalve and a fixed restrictor, a control orifice leading to atmospherebeing provided between the piston housing and the fixed restrictor suchthat when the control valve admits actuating fluid through the fixedrestrictor and the control orifice is uncovered, there will be a loss ofactuating fluid pressure through the open control orifice and the pistonwill not be moved and that when the control orifice is covered, theactuating fluid pressure will increase to a suffrcient value to actuatethe piston. Such an arrangement has the disadvantage that after thepiston has been moved, the actuating fluid pressure will continue to beapplied to the end face of the piston and may increase further until thecontrol valve has been operated to interrupt the supply of actuatingfluid. An object of the invention is to provide a piston valve of theforegoing kind in which the actuating fluid supply is self-cancellingwhen the actuating fluid pressure hasincreased sufficiently to move thepiston valve.

According to the invention a piston valve comprises a housing having aplurality of ports in its peripheral wall between which flow of fluid iscontrollable by a piston in the housing, the piston being movablelongitudinally of the housing between two operative positions in each ofwhich at least some of said ports are interconnected in different pairsthrough passages in said piston, by actuating fluid pressure applied tothe end of said piston appropriate to the movement required,

- the actuating fluid pressure for effecting the movement in onedirection being applied from a source externally of the valve and theactuating fluid pressure for effecting movement in the other directionbeing derived from one of said ports when said piston has been moved insaid one direction, said one port being connected to an end portion ofthe housing adjacent the relevant end face of the piston through arestricted passage, a closable control orifice leading from said passagebetween the restriction therein and said end portion of the housing, thecontrol orifice being openable to prevent the actuating fluid pressurefrom rising sufficiently to effect movement of the piston in said otherdirection and closable to permit the actuating fluid pressure to reach avalue sufficient to efiect movement of the piston in said otherdirection when said movement is to be effected.

Conveniently there are at least three said ports in said housing, theseports being respectively an inlet port to which a fluid to be controlledby the valve is connected, an outlet port for said fluid and said oneport, the piston having a passage therein which in one operativeposition of the piston interconnects said inlet port with said outletport to permit flow of said fluid through the valve and in the otheroperative position in terconnects said inlet port with said one port,instead of said outlet port, thereby interrupting flow of said fluidthrough the valve and instead providing the actuating fluid pressure foreffecting movement of said piston in said other direction when saidcontrol orifice is closed.

The housing may have other inlet and outlet ports arranged tobe'interconnected by passages in said piston, where desired.

At least a pair of piston valves as set out in either of the twoimmediately preceding paragraphs may be so interconnected that an outletport of one of the valves provides the actuating fluid pressure foreffecting movement of the piston of the or another of the valves in saidone direction and an outlet port of said other of the valves isconnected to an inlet port of said one or yet another valve, said inletport being connected through the piston of that valve to said one portthereof to provide the actuating fluid pressure for effecting movementof the piston thereof in said other direction.

By way of example, a piston valve, in accordance with the invention, andits operation will now be described with reference to the accompanyingdiagrammatic drawings, in which:

FIG. 1 shows a conventional piston valve;

FIGS. 2A and 28 respectively show a valve in accordance with the presentinvention in its two operating positions;

FIGS. 3, 4 and 5 are diagrams'illustrating the sequential operation ofthe valve shown in FIG. 2 in moving from one operating position to theother, and

FIG. 6 is a diagram showing four valves of the kind shown in FIG. 2interconnected for automatic operation in sequence.

Referring to FIG. 1, the conventional valve comprises a housing 1containing a piston (not shown) which is movable between two operativepositions in accordance with actuating fluid pressure applied at eitherthe end 2 or 3 in accordance with the direction of movement required.The housing 1 is provided with inlet and outlet ports A, B, C andD whichare interconnected in pairs through passages in the piston dependingupon which operating position the piston is in. The piston is moved inthe direction of the end 2 by fluid pressure applied from an externalsource to the end 3 and it is moved towards the end 3 by fluid pressureapplied at the end 2. The fluid pressure applied to the end 2 is derivedfrom a source4 admitted by means of a control valve 5 to a passage 6containing a fixed restriction 7. Between the fixed restriction 7 andthe end of the housing 2 there is an orifice 8 leading to atmosphere.When the piston has been moved by the application of actuating fluid atthe end 3 to the position in which it is adjacent the end 2, actuatingfluid may be applied through the valve 5 to the passage 6. Assuming thatthe operating orifice 8 is open, the fluid pressure will remain atsubstantially atmospheric pressure but when the operating orifice 8 hasbeen closed, the pressure will increase until the piston is: movedtoward the end 3 of the housing. When this has occurred it is necessaryto release the control valve 5 so that the actuating fluid will beexhausted from the valve 5 through an outlet port 9. However, if thecontrol valve 5 is not released, the fluid pressure will be maintainedin the end portion 2 of the housing and may increase so long as theoperating orifice 8 is closed. This is a disadvantage.

Referring to FIGS. 2A and 2B, the valve in accordance with thisinvention comprises a housing 11 having end portions 12 and 13 and inletand outlet ports A, B, C and D all similar to the corresponding ports inthe conventional valve of FIG. 1. However, in accordance with thepresent invention, the housing has an additional outlet port F (theaforesaid one" port) and also has an outlet port E. The outlet port F isconnected by a passage 16 containing a fixed restrictor 17 to the endportion 12 of the housing 11. A control orifice 18 leading to atmosphereis connected between the fixed restrictor l7 and the end 12 similarly tothe control orifice :8 as shown in FIG. I. When the piston 10 has beenmoved (as shown in FIG. 2A) towards the end 12 of the housing 11 byactuating fluid pressure applied at the end 13, the inlet port C will beconnected through the passage in the piston to the outlet port F and soactuating fluid will be applied to the end 12 of the housing 1 1. Aslong as the operating orifice 18 is open, the fluid pressure applied at12 will be substantially atmospheric but when the control orifice 18 isclosed, the actuating fluid pressure will increase until the piston l0has been moved (as shown in FIG. 28) towards the end 13 of the housing11. As soon as this movement has occurred, the port F will bedisconnected from the inlet port C and therefore actuating fluid willautomatically be disconnected from the end 12 of the housing 11.Therefore there can be no continued application of or increase ofactuating fluid pressure due to failure to open a control valve such asvalve 5 in the valve of FIG. 1 and so the pressure in the passage 16 islimited automatically to the maximum pressure required to move thepiston from the end 12 of the housing 11 towards the end 13.

Turning now to FIGS. 3, 4 and 5, the valve shown in FIG. 2 is againillustrated and furthermore the connections between ports through thepiston in one operative position thereof have been indicated by fulllines and the alternative connections between ports through the pistonin the other operative position thereof have been indicated by brokenlines. The operating orifice 18 has been indicated as a two-port controlvalve. In one extreme position of operation to which the piston has beenmoved by actuating fluid pressure applied at the end 13 is shown in FIG.3 and in this position an inlet port A is connected to an outlet port 8;an inlet port D is connected to an outlet port E and an inlet port C isconnected to the outlet port F which leads to the passage 16. As shownin FIG. 3 the port 18 is open and therefore the fluid applied throughthe port C leads to atmosphere and the pressure at the end 12 of thehousing 11 is substantially atmospheric. Turning now to FIG. 4, thecontrol valve 18 is closed and therefore the pressure in the passage 16increases until it has reached a value sufficient to move the piston tothe left as shown in FIG. 4 until the port B is connected to the port Eand the port C is connected to the port D. During the transition of thepiston from one position to the other, the port C will be in contactwith both ports D and F as shown in FIG. 4. When the piston has beenmoved fully to the left, the port connections will be as shown in FIG. 5and there will be no actuating fluid applied from the port C to the portF.

The valve shown in FIGS. 2 to 5 may conveniently be interconnected withat least two other valves. If, for example three such valves to be used,they may be so interconnected that an outlet port D of one of the valvesprovides the actuating fluid pressure applied at the end 13 of anotherof the valves for effecting movement of the piston thereof in onedirection and an outlet port B of the other of the valves is connectedto an inlet port C of said one valve and through the piston thereof tosaid one port F thereof to provide the actuating fluid pressure appliedat the end 12 of the housing thereof for effecting movement of thepiston of said one valve in said other direction.

FIG. 6 shows how four valves in accordance with the invention can be sointerconnected as to give automatic operation alternately of twocylinders and 21. Each of the valves indicated by 12+, a, a+ and bis thesame as the valve shown in FIGS. 2 to S. In each valve, the port A isconnected to a source of pressure fluid and port E is an exhaust port toatmosphere. The port C of each valve is connected to the port B of thenext valve in sequence; that is port B of valve b+ is connected to portC of b; port B of valve a is connected to port C of valve b+; port B ofvalve (1+ is connected to port C of valve aand port B of valve bisconnected to port C of valve a+. Port D of valve b+ is connected to oneend of a two-position valve 22 controlling cylinder 20 and to the end 13of valve a+. Port D of valve a is connected to the opposite end of valve22 and to the end 13 of valve b. Port D of valve a+ is connected to theend 13 of valve b+ and to one end of a valve 23 controlling cylinder 21.Port D of valve bis connected via an on/off control valve 24 to the end13 of valve aand to the opposite end of valve 23. The control orifices18 of each valve are indicated by the same reference letters as thevalves; i.e. b+, a, 0+ and b. The orifices 18 associated with valve 0-and a+ are controlled differentially by a common closure member 25movable by means of the piston of cylinder 20 and the orifices 18associated with valves b+ and bare controlled differentially by a commonclosure member 26 actuated by the piston of cylinder 21.

The operation of the circuit is as follows: first the on/off controlvalve 24 is placed in the on position in which flow between the port Dof valve band the control valve 23 is completed and the latter is movedto the opposite position to that illustrated. A pressure signal is thenfed through the valve 23 causing cylinder 21 to move from theillustrated position into a position in which the closure member 26 willclose the orifice 18 associated with valve b+. At the end of thatmovement, the valve b+ will be operated by pressure applied at the end12 thereof and port C will be connected to port D and port B to port E.This will cause a pressure signal to be fed from port C to port D ofvalve 1H- causing actuation of valve 22 controlling the cylinder 20,thereby causing the closure member 25 to close the orifice 18 associatedwith valve a. At the same time actuating pressure is applied from port Dof valve b+ to the end 13 of the housing of valve a+ causing it to resetto the position in which port A is connected to port B, port D isconnected to port E and port C is connected to port F in valve a+. Dueto the movement of the closure member 25 to cover the orifice 18 ofvalve 42-, valve ais moved in the direction causing ports C and C and Band E thereof to be connected and thereby causing valve 22 to bereversed and to move cylinder 20 to the position in which the closuremember 25 again closes orifice 18 of valve a+. This causes operatingpressure to be applied to the end 12 of valve a+ causing port C to beconnected to port D and port B to be connected to port E. A signal isthen fed through port C to port D of valve a+ to effect reversal ofvalve 23 to cause the closure member 26 of cylinder 21 to be moved tocover the orifice 18 associated with valve lrand also to cause valve 17+to be reset to the illustrated position in which port A is to beconnected to port B, port D to be connected to port E and port C to beconnected to port F. When orifice 18 of valve 12- has been closed, thebvalve is then set to the position illustrated and a pressure signal isfed through port C to port D of valve bto pass a signal to the on/offcontrol valve 24 and to reset valve ato the position in which port B isconnected to port E and port C is connected to port D. If the on/offcontrol valve 24 is left in the on position then the cycle of operationswill recommence and continue indefinitely until the on/off valve 24 hasbeen switched to the off position. In the latter case, the sequentialoperation will cease when the signal from the b valve is applied to theopen on/off control valve 24. It will be seen that the valves 12+, a, 0+and bare operated continuously in that order, provided the on/offcontrol valve 24 is in the on" position, to effect reciprocation of thetwo cylinders 20 and 21 alternately. It is the provision of theadditional port F in each valve 17+, a-, a+ and b which causes automaticsetting of the valves to enable the sequential operation of the circuitto be performed continuously so long as on/off switch 24 is in the on"position.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

l. A piston valvecomprising a housing having a longitudinally-extendingbore therein, a plurality of ports in the peripheral wall of saidhousing and communicating with said bore, a piston slidablelongitudinally in the bore in the housing between two operativepositions in each of which at least some of said ports areinterconnected in different pairs through passages in said piston, meansfor applying a different source of actuating fluid pressure torespective ends of said piston, whereby the application of one of thesources of actuating fluid pressure to the end of said pistonappropriate to the movement required will effect movement of the pistonfrom one operative position to the other, wherein the improvementcomprises one of said means for applying actuating fluid pressure foreffecting the movement in one direction derives its fluid pressure froma source externally of the valve, and the other of said means forapplying the actuating fluid pressure for effecting movement in theother direction comprises duct means communicating with one port towhich a fluid pressure is applied from a source externally of the valve,said one port being one of one of said pairs of ports, through one ofsaid passages in said piston when the latter has been moved in said onedirection and an end portion of the housing adjacent the relevant endface of the piston, a restriction in said duct means, and a closablecontrol orifice positioned externally of said valve and leading fromsaid duct means between the restriction therein and said end portion ofthe housing, the control orifice being openable to atmosphere to preventthe actuating fluid pressure from rising sufficiently to effect movementof the piston in said other direction and closable to permit theactuating fluid pressure to reach a value sufficient to effect movementof the piston in said other direction when said movement is to beeffected.

2. A piston valve as claimed in claim 1 in which the housing has atleast three ports therein, the ports being respectively an inlet port towhich a fluid to be controlled by the valve is connected, an outlet portfor said fluid and said one port, one of said passages in the piston inone operative position of the piston interconnecting said inlet portwith said outlet port to permit flow of said fluid through the valve andin the other operative position interconnecting said inlet port withsaid one port, instead of said outlet port, thereby interrupting flow ofsaid fluid through the valve and instead providing the actuating fluidpressure for effecting movement of said piston in said other directionwhen said control orifice is closed.

3. A piston valve as claimed in claim 2 having further inlet and outletports interconnectable by another of said passages 6 in the piston.

4. A fluid circuit including four piston valves as claimed in claim 2,said piston valves being so interconnected that an outlet port of afirst of said valves provides the actuating fluid pressure for effectingmovement of the piston of a second of said valves in said one directionand an outlet port of a third of said valves is connected to an inletport of a fourth of said valves, said inlet port being connected throughthe piston of said fourth valve to said one port thereof to provide theactuating fluid pressure for effecting movement of the piston thereof insaid other direction, the circuit also including valve means for openingand closing the control orifices of the four piston valves in sequence

1. A piston valve comprising a housing having a longitudinallyextendingbore therein, a plurality of ports in the peripheral wall of saidhousing and communicating with said bore, a piston slidablelongitudinally in the bore in the housing between two operativepositions in each of which at least some of said ports areinterconnected in different pairs through passages in said piston, meansfor applying a different source of actuating fluid pressure torespective ends of said piston, whereby the application of one of thesources of actuating fluid pressure to the end of said pistonappropriate to the movement required will effect movement of the pistonfrom one operative position to the other, wherein the improvementcomprises one of said means for applying actuating fluid pressure foreffecting the movement in one direction derives its fluid pressure froma source externally of the valve, and the other of said means forapplying the actuating fluid pressure for effecting movement in theother direction comprises duct means communicating with one port towhich a fluid pressure is applied from a source externally of the valve,said one port being one of one of said pairs of ports, through one ofsaid passages in said piston when the latter has been moved in said onedirection and an end portion of the housing adjacent the relevant endface of the piston, a restriction in said duct means, and a closablecontrol orifice positioned externally of said valve and leading fromsaid duct means between the restriction therein and said end portion ofthe housing, the conTrol orifice being openable to atmosphere to preventthe actuating fluid pressure from rising sufficiently to effect movementof the piston in said other direction and closable to permit theactuating fluid pressure to reach a value sufficient to effect movementof the piston in said other direction when said movement is to beeffected.
 2. A piston valve as claimed in claim 1 in which the housinghas at least three ports therein, the ports being respectively an inletport to which a fluid to be controlled by the valve is connected, anoutlet port for said fluid and said one port, one of said passages inthe piston in one operative position of the piston interconnecting saidinlet port with said outlet port to permit flow of said fluid throughthe valve and in the other operative position interconnecting said inletport with said one port, instead of said outlet port, therebyinterrupting flow of said fluid through the valve and instead providingthe actuating fluid pressure for effecting movement of said piston insaid other direction when said control orifice is closed.
 3. A pistonvalve as claimed in claim 2 having further inlet and outlet portsinterconnectable by another of said passages in the piston.
 4. A fluidcircuit including four piston valves as claimed in claim 2, said pistonvalves being so interconnected that an outlet port of a first of saidvalves provides the actuating fluid pressure for effecting movement ofthe piston of a second of said valves in said one direction and anoutlet port of a third of said valves is connected to an inlet port of afourth of said valves, said inlet port being connected through thepiston of said fourth valve to said one port thereof to provide theactuating fluid pressure for effecting movement of the piston thereof insaid other direction, the circuit also including valve means for openingand closing the control orifices of the four piston valves in sequence.